Hammer drills are power tools that can generally operate in three modes of operation. Hammer drills have a tool bit that can be operated in a hammer mode, a rotary mode and a combined hammer and a rotary mode.
Hammer drills, like many power tools, generate a lot of heat during use. In particular, the electric motor of the hammer drill generates large amounts of heat and needs to be cooled. Prior art hammer drill cooling systems are known in which air is drawn into the outer housing of the hammer drill to cool the motor. Prior art hammer drill cooling systems can suffer from the drawback that the air that is drawn into the tool may be contaminated with dust and other materials formed during use of the tool, and if this dust and dirt gets into the moving parts of the transmission mechanism, damage can be caused to the power tool.
Preferred embodiments of the present invention seek to overcome the above disadvantage of the prior art.